Vacuum cleaners are well known and well developed in the prior art. Many attempts have been made previously to create a vacuum cleaner with a suction nozzle capable of cleaning debris located in or on carpeting or other fabric surfaces utilizing a mechanical beating or agitation system such as a rotary brush for dislodging the debris located on the workpiece to be cleaned. There are, however, two inherent disadvantages in a system which mechanically beats the surface to be cleaned. The first of these is that the physical agitation, brushing or beating of the workpiece results in wear upon the workpiece diminishing its appearance and useful life and results in early replacement of the workpiece, and in the mechanical wear of the agitation, brushing or beating apparatus typically located within the suction nozzle housing, thus necessitating repair or replacement.
U.S. Pat. No. 2,558,496 issued to Reeves discloses a mechanical agitator in the form of a brush located in the nozzle inlet of a vacuum cleaner suction nozzle, driven by a hydraulic motor. U.S. Pat. No. 3,813,726 of Kowalewski discloses a vacuum cleaner suction nozzle for use with deep pile shag carpeting containing an agitator in direct contact with the carpet to be vacuumed, driven by an electric motor through a reduction gear assembly.
U.S. Pat. No. 3,750,221 of Meyerhoefer discloses a vacuum cleaner suction nozzle having a vibrator for creating pulsations in the airstream disposed in the throat portion of an air passageway in a suction nozzle. In Meyerhoefer this vibratory member resonates apparently at a prescribed frequency based upon the speed of the airflow moving through the suction nozzle in combination with the properties of the vibrating member. Meyerhoefer does not disclose a mechanical agitator in direct physical contact with the carpeting, however it does disclose a beating mechanism for creating pulsations in the airstream, which mechanism will eventually need to be maintained or replaced in the course of normal operation. Moreover Meyerhoefer does not make provision for adjusting the frequency of its vibrator in operation. Also, Meyerhoefer provides no apparent means for increasing or decreasing the amplitude of the airwaves created by the beating mechanism. Finally, Meyerhoefer provides a vibrator located directly in the airstream, which therefore impedes the airstream and is susceptible to failure should dirt or any other objects obstruct the narrow portion of the air passageway about the vibrator.
None of the known prior art disclose a vacuum cleaner with an air vibration suction nozzle for agitating the workpiece to be cleaned and that contains no moving parts directly in the airstream, and provides a control mechanism for adjusting not only the frequency, but also the amplitude of the airwaves being generated for the purposes of agitating either the workpiece, and/or the debris to be vacuumed. The preferred embodiment described and as claimed below makes provision for agitating either the workpiece and/or debris located in or on the workpiece, depending upon the resident frequency of the object to be vibrated, as well as controls for selecting the frequency to be utilized in agitating the workpiece, and adjusting the amplitude of the airwaves produced by the air vibrating means, coupled with a viewport into the nozzle housing upon the portion of the workpiece to be cleaned, illuminated so that the vacuum cleaner and its suction nozzle can be fine tuned to the task at hand.